Pump jack



2 Sheets-Sheet 1 James 5} Jen sen J. B. JENSEN June 6, 1961 PUMP JACKFiled Aug. 29, 1958 J. B. JENSEN June 6, 1961 PUMP JACK 2 Sheets-Sheet 2Filed Aug. 29, 1958 lllllll I mdfl fi w w H a m 0 I $1,: zK/ i 1 3 7 4 7i A I 5 3 N 1 1 9 l 1 James 5, Jensen INVENTOR.

2,986,948 PUMP JACK James B. Jensen, 14th and Pacific Sts., Colfeyville,Kans. Filed Aug. 29, 1958, Ser. No. 758,093

Claims. (CI. 74-50) The present invention relates to pump jacks and moreparticularly to pump jacks adapted to convert rotary motion toreciprocatory motion for the purpose of imparting reciprocatory motionto a reciprocable polish rod of a pump.

It is an object of the present invention to provide a pump jack having aminimum of parts.

Another object of the present invention is the provision of a pump jackwhich will be of desirably compact size and structural arrangement.

A further object of the present invention is the provision of a pumpjack in which the parts coact in a novel structural relationship so asto reduce the number of hearing surfaces and supporting elements.

Finally, it is an object of the present invention to provide a pump jackwhich will be simple and inexpensive to manufacture, easy to assemble,disassemble, repair and maintain, and rugged and durable in use.

Broadly, these objects are achieved by providing a pump jack which isessentially a sandwich of four parts. The two outer parts are halves ofthe pump jack housing and the two inner parts are a rotor and acrosshead to which reciprocatory movement is imparted by the rotor. Thetwo inner parts are supported entirely by bearing contact with eachother and with the two housing halves.

Other objects, features and advantages of the present invention willbecome apparent from a consideration of the following description, takenin connection with the accompanying drawings, in which:

FIGURE 1 is a perspective view of the exterior of a pump jack accordingto the present invention, shown in its operative environment includingthe polish rod of a reciprocatory pump;

FIGURE 2 is a fragmentary perspective view showing the bearinginterrelationships of the crosshead and th cover plate of the pump jackhousing;

FIGURE 3 is a cross-sectional view taken on the line 3-3 of FIGURE 4;and

FIGURE 4 is an elevational view of the present invention with the coverplate removed and with various operational positions of the parts shownin full line and in phantom line, the full line representation showingthe parts during the up stroke.

Referring now to the drawings in greater ,detail, there is shown a pumpjack indicated generally at 1 adapted to impart reciprocatory movementto the polish rod 3 of a reciprocatory pump (not shown). The pump jackcomprises a housing 5 made up of a base portion 7 to which a cover plate9 is detachably secured by means of bolts 11. Base portion 7 has abearing boss 13 in which is mounted for rotation a pinion gear stubshaft 15 having a pinion gear 17 on its inner end within housing 5. Onits outer end, outside housing 5, shaft 15 carries a V pulley 19 whichis keyed thereto and which is driven by an endless V belt 21 by means ofa smaller V pulley on the drive shaft of an electric motor or otherdrive means (not shown).

The gear teeth of pinion gear 17 are in mesh with peripheral gear teeth23 on a circular rotor 25. Rotor 25 has an axial hub 27 which has acylindrical outer contour and which is mounted for rotation in a hollowgenerally cylindrical sleeve 29 which is integral with the remainder of,and comprises a portion of, base portion 7 of housing 5. In theembodiment shown, sleeve 29 provides spaced cylindrical bearing surfacesin bearing con- States Patent tact with the cylindrical outer contour ofhub 27; and it will of course be appreciated that the over-allconfiguration of sleeve 29 is immaterial so long as it providescylindrical bearing surfaces suitable to provide radial support in alldirections for hub 27 and hence for rotor 25 as a whole. Likewise, it isimmaterial whether sleeve 29 is integral with base portion 7.

At its inner end, sleeve 29 has annular bearing surfaces 31 which are inbearing contact with complementary annular bearing surfaces 33 formed onan annular abutment shoulder of rotor 25. In the illustrated embodiment,the bearing surfaces 31 and 33 are uniplanar in a plane perpendicular tothe axis of rotation of rotor 25; but it will of course be understoodthat they could be conical about the axis of rotation of the rotor orhave other shapes provided only that these surfaces be disposed at asubstantial angle to the axis of rotation of the rotor and that thegeneratrices of these surfaces rotate about an axis coincident with theaxis of rotation of rotor 25. In this way, sleeve 29 provides radialbearing support for rotor 25 in all directions and axial bearing supportfor rotor 25 in one axial direction. Of course, it will be understoodthat the use of ball hearings or roller bearings or other anti-frictiondevices or the like between rotor 25 and base portion 7 does not alterthe essential operative characteristics of the bearing structure betweenthese two members; but a highly desirable feature of the preferredembodiment of the present invention is that such auxiliary bearingdevices are unnecessary.

Also mounted in housing 5, but for rectilinear reciprocatory movement,is a crosshead 35. Crosshead 35 includes a pair of spaced guide members37 and 39 which have confronting, generally parallel track surfaces 41and 43 thereon, respectively. Rotor 25 has a bearing boss 45 disposedeccentrically thereon which carries a crank pin 47. Crank pin 47 iscomprised of three parts: a short axle 49 which is mounted in bearingboss 45 and the axis of which is parallel to the axis of rotation ofrotor 25; a roller 51 mounted for rotation on an end of axle 49 on thecrosshead side of bearing boss 45; and a retaining nut 53 on ascrew-threaded end of axle 49 on the opposite side of bearing boss 45.The roller of crank pin 47 is disposed between and has rolling contactwith track surfaces 41 and/or 43 in all positions of rotor 25 andcrosshead 35 relative to each other, as seen in FIGURE 4. Thus, tracksurfaces 41 and 43 define between them a slot within which crank pin 47moves.

Rotor 25 and crosshead 35 have bearing contact with each other in allpositions. To this end, rotor 25 is provided with an annular abutmentflange 55 which carries on its crosshead side a uniplanar bearingsurface of which the plane is perpendicular to the axis of rotation ofrotor 25. Spaced guide members 37 and 39, in turn, carry on their rotorside spaced uniplanar bearing surfaces which are also perpendicular tothe axis of rotation of rotor 25 and which are in bearing contact withsubstantial areas of the coacting bearing surfaces of flange 55 of rotor25 in all positions of rotor 25 and crosshead 35. For this reason,flange 55 of rotor 25 is made of as great a diameter as possible so asto provide as great contact bearing areas with crosshead 35 as possibleand to assure that the spaced areas of contact will be spaced apart bydistances as great as possible so as to assure the greatest stability ofthe contacting parts 25 and '35. It will of course be appreciated thatflange 55 need not be annular in order to achieve this result. Instead,flange 55 could have a variety of closed configurations other thancircular, or could be in the form of an enlarged bearing boss coveringthe area which includes the axis of rotation of rotor 25; but theannular configuration of flange 55 is preferred not onlyfor ease andprecision of manufacture but also for the uniform precision of operationwhich is available with this configuration. It will also be observedthat hearing boss 45 could be positioned at a variety of distancesradially of the axis of rotation of rotor 25; but it is preferred thatthis boss be bisected by annular flange 55 so that the bearing surfaceof the flange is a uniplanar continuation of the bearing surface betweenboss 45 and roller '51 so as to enable accurate positioning of roller51. From a consideration of the arrangement just described, it will beevident therefore that crosshead 35 provides axial support for rotor 25in one direction and that bearing surfaces 31 of sleeve 29 of housing 5provide axial support for rotor 25 in the other direction, so thatsleeve 29 and crosshead 35 provide the sole support necessary to retainrotor 25 accurately in its operative position.

Crosshead 35 also includes a pair of spaced parallel stabilizer members57 and 59 which are disposed at a substantial angle to track surfaces 41and 43, preferably 90. The stabilizer members extend across and bridgebetween spaced guide members37 and 39 and maintain the latter inaccurately spaced relationship with a minimum of parts. As also seen inFIGURE 3, members 57 and 59 are on one side of guide members 37 and 39,and thus leave the entire confronting surfaces of members 37 and 39comprising track surfaces 41 and 43 available for rolling contact withroller. 51.

In addition to spacing apart guide members 37 and 39, stabilizer members57 and 59 perform the function of confining the reciprocatory movementof crosshead 35 to a rectilinear path. For this, purpose, stabilizermembers 57 and 59 are provided with confronting guide surfaces 61 and63, respectively, and an elongated rib 65 on the interior of cover plate9 has corresponding guide surfaces with which guide surfaces 61 and 63are in slidable bearing contact. Also, stabilizer members 57 and 59 areprovided with guide surfaces 67 and 69 which have slidable bearingcontact with corresponding guide surfaces on rib 65 of cover plate 9.Thus, guide surfaces 61 and 63 coact with corresponding guide surfaceson the cover plate to restrain crosshead 35 to a rectilinear path ofmovement, while guide surfaces 67 and 69coact with corresponding guidesurfaces on the cover plate to prevent displacement of crosshead 35 inany direction having a component along the axis of rotation of rotor 25.In the illustrated embodiment, guide surfaces 6'1 and 63 are shown to beparallel to each other, while guide surfaces 67 and 69 are shown to becoplanar with each other and perpendicular to surfaces 61 and 63.However, it will be apparent that the various bearing surfaces showncould be reduced in number, as by replacing sur faces 61 and 67 with asingle inclined surface and by replacing surfaces 63 and 69 by a singleinclined surface. Thus, the essential operative relationships of theinterengaged bearing surfaces of crosshead 35 and cover plate 9 are thatthere be at least two bearing interfaces, at least one of which must beat a substantial angle to the axis of rotation of rotor 25 so as to holdcrosshead 35 against rotor 25, and at least two of which must bedisposed at substantial angles to a plane perpendicular to the axis ofrotation of rotor 25 so as to confine crosshead 35 to a rectilinear pathof movement. The first interface may be one of the two latterinterfaces; and it is not necessary that the interfaces be planar orspaced apart, as they could be defined by a continuous arcuateinterface. It is necessary, however, that the interfaces betweencrosshead 35 and cover plate 9 have uniform cross-sectionalconfigurations in planes perpendicular to the line of movement ofcrosshead 35 over a substantial distance.

In the embodiment shown, rib 65 on cover plate 9 is disposed betweenstabilizer members 57 and 59 of crosshead 35. .A possible alternativeconstruction is that a rib on crosshead 35 be disposed between a pair ofspaced parallel ribs on cover plate 9, but this alternative is lesspreferred than that shown, as the provision of spaced stabilizer members'57 and 59 lends the greatest strength and rigidity to crosshead 35 withthe least weight.

In this connection, it is important to note that the location of members57 and 59' across the ends of members 37 and 39 also lends stability tothe assembly during the up or working stroke, as roller 51 is thenroughly in line with members 57 and 59 and does not tend to cant them intheir guides. During the down stroke, roller 51 is in a position to cantcrosshead 35 but does not as the load is relatively very small.

It will therefore be apparent that the position of crosshead 35 axiallyof rotor 25 is fixed by its bearing contact with and between rotor 25and cover plate 9 and that the position of crosshead 35 along its pathof rectilinear movement perpendicular to the axis of rotor 25 is fixedby the rotated position of crank pin 47 In all non-vertical positions oftrack surfaces 41 and 43, at least a portion of the weight of crosshead35 and the members carried thereby will be borne by crank pin 47; andhence, a counterweight 71 is secured to the end of hub 27 of rotor 25 bya bolt 73 in diametric opposition to crank pin 47.

As seen in FIGURES 1 and 4, the upper ends of stabilizer members 57 and59 are housed within an extension of housing 5 comprising an elongatedcover 75 having a longitudinally extending slot 77 through the side wallthereof. Cover 75 is of sheet metal detachably forcefitted on acorresponding adaptor portion of housing 5. The upper ends of stabilizermembers 57 and 59 carry between them a bracket 79 which coacts with adetachable clamp 81 to secure polish rod 3 in unitary assembly with andparallel to stabilizer members 57 and 59 and in parallelism to the pathof rectilinear movement of crosshead 35. To this end, bracket 79 extendsoutside housing 5, and specifically outside cover 75 through slot 77.

The operation of the device of the present invention is that uponrotation of power driven pinion gear 17, rotor 25 is driven to rotateabout its axis and crank pin 47 moves in a circular orbit within theslot defined between track surfaces 41 and 43 of crosshead 35. Crosshead35- is thus reciprocated along the path defined by its bearing contactwith cover plate 9, thereby to reciprocate the unitary polish rod of thepump to be driven.

To assemble the device, with the pinion gear 17 already in place andwith cover plate 9 removed, it is necessary only to insert rotor 25 withteeth 23 in mesh with those of pinion gear 17 and with hub 27 in sleeve29. Counterweight 71 can be attached at this or any later stage. Next,crosshead 35 is inserted with track surfaces 41 and 43 on either side ofcrank pin 47; and finally, cover plate 9 is laid on the assembly withrib 65 between stabilizer members 57 and 59. The tightening of bolts 11completes the assembly of the jack proper. Cover 75 is then added, andthe securement of polish rod 3 on bracket 79 by means of clamp 81completes the assembly.

It will be seen that a very compact and simple structural arrangement isprovided in which the rotor and the crosshead are maintained inassembled relationship by hearing contact with each other and with thetwo housing halves. Thus, there are three critical bearingrelationships: that between the rotor and the base portion of thehousing, that between the rotor and the crosshead, and that between thecrosshead and the cover plate. To summarize these relationships, abearing surface between the base portion of the housing and the rotormust be disposed at a substantial angle to the axis of rotation of therotor and the generatrix of this surface or generatrices of thesesurfaces must have an axis of rotation coincident with that of therotor. The bearing surfaces between the rotor and the crosshead must beuniplanar in a plane perpendicular to the axis of rotation of the rotor.The hearing surfaces between the crosshead and the cover plate must beat least two in number and must include at least one disposed at asubstantial angle to the axis of rotation of the rotor and at least twodisposed at a substantial angle to a plane perpendicular to the axis ofrotation of the rotor.

From a consideration of the foregoing disclosure, it will be obviousthat all of the initially recited objects of the present invention havebeen achieved.

Although the present invention has been described and illustrated inconnection with preferred embodiments, it is to be understood thatmodifications and variations may be resorted to without departing fromthe spirit of the invention, as those skilled in this art will readilyunderstand. Such modifications and variations are considered to bewithin the purview and scope of the present invention as defined by theappended claims.

What is claimed is:

1. For use with a pump having a reciprocable drive element, a pump jackcomprising a housing having a base portion and a cover plate detachablysecured to the base portion, the base portion having a hollow generallycylindrical sleeve extending therethrough, the sleeve having an innerend disposed within the housing, a rotor having an axial hub mounted forrotation in the sleeve, the rotor and the inner end of the sleeve havinginterengaged bearing surfaces disposed at a substantial angle to theaxis of rotation of the rotor, said surfaces having generatrices thatrotate about said axis, a crank pin mounted on the rotor a substantialdistance from the axis of rotation of the rotor, a crosshead mounted forreciprocatory movement in the housing, the rotor and the crossheadhaving interengaged uniplanar bearing surfaces lying in a common planeperpendicular to said axis of rotation, the crosshead having a slot inwhich the crank pin is disposed, the slot being disposed at an angle tothe direction of reciprocatory movement of the crosshead, the crossheadand the cover plate having interengaged bearing surfaces disposed at asubstantial angle to said axis of rotation and said common plane, thelast-named bearing surfaces being defined by an infinite number ofstraight lines parallel to each other and to a line perpendicular tosaid axis of rotation, drive means for rotating the rotor, and a bracketcarried by the crosshead and adapted to be detachably secured to areciprocable drive element of a pump.

2. For use with a pump having a reciprocable drive element, a pump jackcomprising a housing having a base portion and a cover plate detachablysecured to the base portion, a rotor mounted for rotation in the housingon the base portion about a horizontal axis, a crank pin mounted on therotor a substantial distance from the axis of rotation of the rotor, acrosshead mounted for vertical reciprocatory movement in the housing,the crosshead having a pair of horizontally disposed, verticallyspaced-apart members defining between them a horizontal slot in whichthe crank pin is disposed, a pair of elongated spaced parallel verticalslide members rigidly interconnecting said horizontal members on theside of said horizontal members opposite the rotor, the cover platehaving a guide portion disposed between said vertical slide members,said guide portion and vertical slide members having interengagedvertical bearing surfaces disposed at a substantial angle to said axisand to a plane perpendicular to said axis, drive means for rotating therotor, and a bracket carried by said vertical slide members and adaptedto be detachably secured to a reciprocable drive element of a pump. a

3. Apparatus as claimed in claim 2, the crank pin when rising beingdisposed on one side of the vertical plane in which said axis lies, andthe vertical plane which is midway between said vertical slide membersand parallel to said vertical plane in which said axis lies being onsaid one side of said vertical plane in which said axis lies, the saidvertical slide member farthest from said axis being at least as far fromsaid axis as the crank pin.

4. For use with a pump having a reciprocable drive element, a pump jackcomprising a housing having a base portion and a cover plate detachablysecured to the base portion, a rotor mounted for rotation in the housingon the base portion about a horizontal axis, a crank pin mounted on therotor a substantial distance from the axis of rotation of the rotor, acrosshead mounted for vertical reciprocatory movement in the housing,the crosshead having a slot in which the crank pin is disposed, the slotbeing disposed at an angle to the direction of reciprocatory movement ofthe crosshead, drive means for rotating the rotor, and a bracket carriedby the crosshead and adapted to be detachably secured to a reciprocabledrive element of a pump, the crank pin when rising being disposed on oneside of the vertical plane in which said axis lies, and the bracketbeing also disposed on said one side of said vertical plane.

5. For use with a pump having a reciprocable drive element, a pump jackcomprising a housing having a base portion and a cover plate detachablysecured to the base portion, a rotor mounted for rotation in the housingon a shaft extending through the base portion about a. horizontal axis,a crank pin mounted on the rotor a substantial distance from the axis ofrotation of the rotor, a crosshead mounted for vertically reciprocatorymovement in the housing, the crosshead having a slot in which the crankpin is disposed, the slot being disposed at an angle to the direction ofreciprocatory movement of the crosshead, drive means for rotating therotor, a bracket carried by the crosshead and adapted to be detachablysecured to a reciprocable drive element of a pump, and a counterweightfixed to the shaft outside the housing and having its center of gravitya substantial distance from said axis directly opposite the crank pinrelative to said axis.

References Cited in the file of this patent UNITED STATES PATENTS923,644 Griggs June 1, 1909 1,403,632 Recen Jan. 17, 1922 1,449,785Selby Mar. 27, 1923 1,451,691 Frederick Apr. 17, 1923 1,867,307Carpenter July 12, 1932 2,055,041 Miller Sept. 22, 1936 2,301,967 Moskeret al. Nov. 17, 1942 2,677,966 Mueller May 11, 1954 2,699,745 Ayres Jan.18, 1955 2,704,941 Holford Mar. 29, 1955 FOREIGN PATENTS 435,386 FranceDec. 23, 1911

